I wouldn't get too excited.
The source of the news says that the Mac Pro and Mac Mini
SERVER versions are supply constrained. This makes perfect sense. I personally expect the Mac Pro and Mac Mini Server variations to EOL and not be replaced with anything.
It's being widely reported out of WWDC that Lion Server will be an App Store purchase going forward. Therefore, it doesn't make sense for Apple to offer them as a BTO option anymore... so sell down the existing stock and EOL them. People can then just buy the regular models and add the Server software after purchase.